Pneumatic hand former



June 22, 1954 5, RAYMOND 2,681,683

PNEUMATIC HAND FORMER Filed July 17. 1950 2 Sheets-Sheet l INVENTOR.

ROGER 5. RA YMOND ATTORNEY June 1954 R. s. RAYMOND 2,681,683

PNEUMATIC HAND FORMER Filed July 17. 1950 '2 Sheets-Sheet '2 Winn IlllINVENTOR. ROGER S. RAYMOND By W164 ATTORNEY Patented June 22, 1954UNITED STATE ATEN'I' OFFICE PNEUMATIC HAND FORMER Roger S. Raymond,Itedondo Beach, Calif., as-

signor to North American Aviation, Inc.

3 Claims.

The present invention relates to means for performing hand finishingoperations on formed sheet metal parts. Formed parts made from sheetmaterial such as the aluminum alloys commonly employed in aircraftconstruction are frequently made by hydropress operations. While thistype of forming provides for rapid production of parts with a minimumamount of too1- ing, the parts may require certain hand finishingoperations in order to obtain the desired detailed contours anddimensional tolerances. In the past it has been common practice toperform these finishing operations by hand as a bench operation by theuse of a rawhide mallet. The present invention provides means foraccomplishing such finishing operations in an expeditious manner bysuccessively bringing the various portions of the work piece intocontact with a power driven head. The operator causes to be directed aseries of short quick blows to efiect close conformity of the finishedpart to the die or form block.

It is therefore an object of the present invention to provide means forperforming finishing operations on sheet metal parts.

It is also an object to provide such means which are rapid and highlyeffective in operation.

It is a further object of the present invention to provide sheet metalfinishing means which are simple to operate, inexpensive to constructand which are readily adaptable to the finishing operations of a greatvariety of shapes and contours.

Other objects of invention will become apparent from the followingdescription taken in connection with the accompanying drawings, in whichFig. 1 is a top plan view of the subject sheet metal forming equipment,

Fig. 2 is a front elevational view,

Fig. 3 is a section taken at the line 3-3 of Fig. 4, and

Fig. 4 is a longitudinal sectional view taken on the line 4-4 of Fig. 1.

Referring to the drawings, the unit comprises a percussion typepneumatic motor I driven by compressed air, the rate and amplitude ofthe stroke of which may be varied by the pressure of the air admittedthereto. The motor unit is positioned upon a work surface 2 by means ofyokes 3-4 secured to the work surface by pairs of bolts 5-5 and 6-6. Theyokes are arranged to engage the body of the motor I and are providedwith lugs 1-1 and 8-8 through which the bolts pass. The yokes are alsoprovided with upwardly extending tabs 9 and I6 interconnected by alongitudinal plate H. The motor is resiliently mounted by means of compression type coil springs l2 provided about the shanks of the hold downbolts 5 and 6, bearing against washers is at the under surfaces of thebolt heads and upon the upper surfaces It of the lugs 1-8 of the yokes 3and 4. Spacers :5 are provided beneath the lugs 8 for supporting therear yoke 13 to position the unit with respect to the surface 2, thefront yoke 3 being carried upon adjustable means to be hereinafter morefully described.

The forward portion of the motor l is provided with a percussive head 23which. is positioned between a pair of guiding elements 2 l-ZZ formed ofshort angle sections placed back to back. The percussive head 2!! isaccordingly guided for limited fore and aft movement and is restrainedfrom side movement. Small tabs 23-24 are also provided to prevent thepercussive head from becoming displaced upwardly beyond a certainlimited amount. A work engaging face piece 25 is provided on thepercussive head. The face piece may be made of any suitable durable andnon-abrasive material and a form of impregnated fiberboard known to thetrade as red fiber may be very satisfactorily employed.

Referring now to Fig. 4 the work piece may be seen indicated in phantomat 3B in position upon the die block 3|. The motor I is arranged to beactuated by means of an air control valve 32 which controls theadmission of compressed air through the line 33 into the cylinder of themotor i. Automatic actuation of the unit is provided when the work pieceis brought in contact with the face piece 25. This is accomplished bythe following arrangement wherein a control rod 34 is supported andjournaled for limited sliding movement in the pair of upstanding tabs9-10 attached respectively to the forward and rear yokes 3-4. Theforward portion of the rod 34 carries a depending plate 31 which engagesthe spherical-ended connecting link 33 between the forward portion 39 ofthe motor and the percussive head '28. The rear end of the rod 34terminates in a flattened head 35 which bears upon an arm 36 of a bellcrank it pivotally mounted at 42 between a pair of plate members 43, theopposite arm 44 bearing upon the motor air control valve 32. Pressure ofthe work piece 39 against the face piece 25 is transmitted throughelements 20-38-31 to the 3 rod 34 which in turn actuates the controlvalve 32 through the action of the bell crank ll. Integral with the rod34 is an annular shoulder 65 against which compression spring 56 bears,the other end of the spring being seated against plate 10. The workpiece pressure mustovercome the spring to actuate the control valve 32and the spring 45 returns the control linkage upon relaxing the workpiece pressure, releasing the control valve '32, which is also springloaded to the closed position. Adjustment means on the rod 3% forcontrol of the actuation of the air valve 32 is provided by means of athreaded portion til which engages a fitting 48 integral with the plate'37. A lock nut AS'bears against the forward face of the plate 31 tosecure the rod. V

35 in adjusted position. I

To accommodate angles other than 90 on flanged portions of the workpieces the entire motor and its associated mechanism .may be tilted withrespect to the work surface. This is accomplished by means of a handcontrol 5?: having a shaft 51 which is threaded at 52 for engagementwith a corresponding threaded vertical bore in the work surface 2. Belowthe Work surfaee the shaft 5! has an extension ts which bears at 915against the upper surface of one end. of a pivoted lever 55. The leveris pivoted at 56 upon a pair of brackets 51 which depend from the lowerface of the work surface. The

forward end of the lever 55 bears at 52 against a the under surface ofthe forward yoke 3. When the shaft extension 53 is moved downwardly theforward end of the motor unit is raised accordingly. This movement iseifected against the tension of the springs '12 which bear upon the iugsi of the forward yoke '3. The lugs of the yokes 3 and 4 are providedwith slightly enlarged openings at '59 through which the bolts and 5pass and accordingly the yokes may be tilted sufficiently to accommodatethe desired angular adjustment. Raising the forward end of the motortends to vary the angular relationship of the front face of the member29 with respect to the work surface 2.. Where angular adjustment inexcess of that obtainable is required the face of the element 25 may bebeveled or appropriately contoured.

Although the invention has been described and illustrated in detail, itis to be clearly understood that the same is by way of illustration andexample only and is not to be taken by way of limitation, the spirit andscope of this inven- 4 tion being limited only by the terms of theappended claims.

I claim:

1. A device for finishing sheet material on a die comprising a worksupporting member adapted to support said die; a pneumatic percus iontype motor carried by said member; a percussive head carried by saidmotor for reciprocal movement in a path fixed relative thereto uponactuation of said motor; a source of pressurized air connected with saidmotor for operation thereof; valve means associated with said motor fornormally preventing entrance of saidpressurized air into said motor forprecludoperation thereof; and mechanical means interconnecting saidpercussive head and said valve means whereby said valve means isresponto pressure on said percussive head for allowing entrance of saidpressurized into said motor for permitting operation thereof.

2. A device as recited in claim 1 including in addition means forvarying the angle of said motor relative to said work supporting memberwhereby said path of said percussive head is varied.

3. Apparatus for finishing sheet material comprising a percussion typepneumatic motor, a percussive head driven by said motor in a pathdefined thereby; a pair of yokes secured to said motor; a supportmember; spring means urging said yokes toward said support member; andmeans adapted to pivot said motor with respect to said support inopposition to said spring means whereby said path of said percussivehead is adjusted.

References Cited in the file of this patent UNITED STATES PATENTS

